The present invention relates generally to the field of IP telephony, and more particularly to providing intelligent network control services in IP telephony.
Internet telephony is the real-time delivery of voice, and other multimedia data, between two or more parties across a network using Internet protocols (IP). Internet telephony began in the mid-1990s with the introduction of Internet phone software. Internet phone software is designed to run on a personal computer equipped with a sound card, speakers, microphone, and modem. Software compresses the voice signal and translates it into IP packets for transmission over the Internet. This basic PC-to-PC Internet telephony works, however, only if both parties are using Internet phone software.
Internet telephony offers the opportunity to design a global multimedia communications system that may eventually replace the existing circuit switched telephony infrastructure. In a relatively short period of time, Internet telephony has advanced rapidly. Many software developers now offer PC telephony software.
Internet telephony is session based rather than connection based. Generally, a first Internet protocol, such as H.323 or Session Initiation Protocol (SIP) is used to establish the session and negotiate the capabilities for the session, and a second Internet protocol, such Real-time Transport Protocol (RTP), is used to transport the actual media across the UP network.
While IP telephony offers benefits to both users and carriers in terms of cost and variety of media types, there is a substantial installed base of traditional telephones served by the public switched telephone network (PSTN). Moreover, in addition to its widespread nature, the PSTN offers a rich set intelligent network services such as xe2x80x9c800xe2x80x9d number services, Virtual Private Network (VNET) services, call forwarding, and the like. Accordingly, IP telephony is not likely, anytime soon, to replace the PSTN. However, there is a desire to integrate the PSTN with IP networks, including the Internet and private intranets. Thus, there are instances when a call originated by a phone on the PSTN will be required to be carried through an IP based network for eventual delivery to a second phone on the PSTN. There is a further desire to provide all of the intelligent network services that currently exist in the PSTN to IP telephony calls.
The present invention provides a method of and system for providing intelligent network control services in IP telephony. The system includes a location-manager and an IP telephony proxy server. The location manager includes an interface to a legacy telephony service control entity, such as service control point (SCP). The IP telephony proxy server, which may be, for example, an H.323 gatekeeper or a Session Initiation Protocol (SIP) proxy server, includes an IP interface to the location manager.
When the IP telephony proxy server receives a request to initiate an IP telephony session or call to a called party address or number, the IP telephony proxy server determines if it needs intelligent network services in order to route the request to the called party address or number. Examples of sessions requiring intelligent network services are xe2x80x9c800xe2x80x9d calls and virtual private network (VNET) calls. If the IP telephony proxy server requires intelligent network services, the IP telephony proxy server sends an IP telephony session initiation request to the called party at the location manager. The location manager uses the information received from the IP telephony proxy server to query the legacy telephony service control entity for routing information. When the location manager receives a routing response from the service control entity, the location manager maps the response to an IP telephony session control message back to the IP telephony proxy server.